Embolic protection device

ABSTRACT

The embolic protection device ( 10 ) has an expandable tubular structure supporting a filter mesh material ( 12 ). The embolic protection device is compressed to a small diameter for insertion into a patient&#39;s aorta, then expanded within the aorta with the filter mesh material positioned to allow blood to enter sidebranch vessels connected to the aorta and to prevent embolic material from entering the sidebranch vessels. The filter mesh material may be configured with waves or undulations ( 26 ) for increased surface area and/or with two layers of mesh material to provide additional protection against embolization and to prevent inadvertent occlusion of the sidebranch vessels.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.13/347,046 (Attorney Docket No. 41959-703.302), filed Jan. 10, 2012,(now U.S. patent application Ser. No. ______) which is a continuation ofU.S. patent application Ser. No. 10/493,854 (Attorney Docket No.41959-703.831), filed Apr. 27, 2004, (now U.S. Pat. No. 8,114,114) whichis a National Stage Application of PCT/US2003/26938 (Attorney Docket No.41959-703.601), filed Aug. 27, 2003, which claims the benefit of U.S.Provisional Application No. 60/406,492 (Attorney Docket No.41959-703.101), filed Aug. 27, 2002, the full disclosures of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention.

The present invention relates to apparatus and methods for providingembolic protection to a patient's aortic arch vessels during cardiacsurgery and interventional cardiology procedures.

Cerebral embolism is a known complication of cardiac surgery,cardiopulmonary bypass and catheter-based interventional cardiology andelectrophysiology procedures. Embolic particles, which may includethrombus, atheroma and lipids, may become dislodged by surgical orcatheter manipulations and enter the bloodstream, embolizing in thebrain or other vital organs downstream. Cerebral embolism can lead toneuropsychological deficits, stroke and even death. Prevention ofcerebral embolism would benefit patients and improve the outcome ofthese procedures.

Previous devices for preventing cerebral embolism are described in thefollowing U.S. patents and patent applications, which are herebyincorporated by reference: U.S. Pat. No. 6,371,935 Aortic catheter withflow divider and methods for preventing cerebral embolization, U.S. Pat.No. 6,361,545 Perfusion filter catheter, U.S. Pat. No. 6,254,563Perfusion shunt apparatus and method, U.S. Pat. No. 6,139,517 Perfusionshunt apparatus and method, U.S. Pat. No. 6,537,297 Methods ofprotecting a patient from embolization during surgery, U.S. Pat. No.6,499,487 Implantable cerebral protection device and methods of use,U.S. Pat. No. 5,769,816 Cannula with associated filter, US20030100940A1Implantable intraluminal protector device and method of using same forstabilizing atheromas.

BRIEF SUMMARY OF THE INVENTION

The present invention takes the form of apparatus and methods forproviding embolic protection to a patient's aortic arch vessels duringcardiac surgery and interventional cardiology and electrophysiologyprocedures. Embolic particles in the aortic blood flow are preventedfrom entering the aortic arch vessels and carotid arteries that lead tothe brain. The apparatus and methods of the present invention can alsobe used for embolic protection of other organ systems, such as the renalsystem.

In one embodiment, a stent-like embolic protection device is constructedof a self-expanding tubular mesh that may be woven out of wires orfibers or formed from a tube or sheet. The embolic protection device iscompressed to a small diameter and inserted into a delivery tube orcatheter, which is introduced via a peripheral artery or an aortotomyand advanced into the aortic arch. Once in place, the delivery tube iswithdrawn to allow the device to expand similar to a self-expandingstent. The mesh of the device covers the ostia of the arch vessels,allowing blood to enter, but preventing potential emboli from enteringthe aortic arch vessels and carotid arteries. The device conformsclosely to the walls of the aorta so that it will not interfere withperforming cardiac surgery or interventional cardiology procedures. Theembolic protection device may be collapsed and withdrawn from the aortaafter the procedure or it may be left in the aorta for long-term embolicprotection.

In another embodiment, the embolic protection device may be made with aflat panel of fine mesh textile fabric that is supported on a wire frameor the like. The panel of fine mesh fabric is held in place over theaortic arch vessels by the wire frame to filter out potential emboli.Being made of fabric, the device is free to conform to the ostia of thearch vessels to allow more surface area for blood flow compared to aflat panel. The wire frame may be attached to a handle or cannula forinsertion through an aortotomy or to a catheter for peripheral arteryinsertion. In addition, the wire frame may include one or more wirehoops or a stent-like tubular structure for supporting the embolicprotection device within the aortic arch.

Additional features are described which may be used with eitherembodiment of the embolic protection device. An embolic protectiondevice is described with waves or undulations to provide more surfacearea for filtering out potential emboli and to prevent inadvertentocclusion of the arch vessels. Another embolic protection device isdescribed with two layers of mesh material to provide additionalprotection against embolization and to prevent inadvertent occlusion ofthe arch vessels. An embolic protection device is described with aninflatable toroidal balloon for supporting the filter mesh materialwithin the aorta. The embolic protection device or a portion of it maybe coated with an antithrombogenic coating to reduce the formation ofclots that could become potential emboli.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a stent-like embolic protection device deployed within apatient's aortic arch for protecting the aortic arch vessels and carotidarteries from potential emboli.

FIG. 2 shows a stent-like embolic protection device with waves orundulations.

FIG. 3 shows a cut-away view of a stent-like embolic protection devicewith two layers of mesh material.

FIG. 4 shows an alternative embodiment of an embolic protection device.

FIG. 5 shows another alternative embodiment of an embolic protectiondevice.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a stent-like embolic protection device 10 deployed within apatient's aortic arch for protecting the aortic arch vessels and carotidarteries from potential emboli. The embolic protection device 10 is madeof a resilient material, either a polymer or a metal (e.g. Nitinol) or acombination of materials. The device 10 may be woven out of wires orfibers to form a tubular mesh structure 12 or by slitting and expandinga tube or sheet. Alternatively, the device 10 may be constructed with atubular mesh structure 12 made of a flexible textile mesh with one ormore wire hoops or a stent-like tubular structure for supporting thetubular mesh structure 12 within the aortic arch. The device 10 iscompressible to a small diameter for insertion into the aorta viaperipheral artery access or through an aortotomy. The device 10 ispreferably self-expanding and, when expanded, has a generally tubularshape that conforms to the diameter and curvature of the aortic arch.

The embolic protection device 10 is compressed to a small diameter andinserted into a delivery tube or catheter 14. The delivery tube isintroduced via a peripheral artery or an aortotomy and advanced into theaortic arch. Once in place, the delivery tube 14 is withdrawn to allowthe device 10 to expand similar to a self-expanding stent. The mesh 12of the device covers the ostia of the arch vessels, allowing blood toenter, but preventing potential emboli from entering the aortic archvessels and carotid arteries. The device 10 conforms closely to thewalls of the aorta so that it will not interfere with performing cardiacsurgery or catheter-based interventional cardiology or electrophysiologyprocedures.

Alternatively, the embolic protection device 10 may beballoon-expandable. In this case, the embolic protection device 10 wouldbe crimped or compressed onto an expandable balloon mounted on acatheter. The catheter is introduced into the aortic arch and theballoon is expanded to deploy the embolic protection device 10 in theaorta. Other volume expanding mechanisms, such as a mechanical expander,may be used in lieu of an expandable balloon.

After the procedure is completed, the embolic protection device 10 maybe compressed and withdrawn from the aorta. Alternatively, the device 10may be left in the aorta for long-term embolic protection. The device 10may be compressed using one or more drawstrings 16 that encircle thedevice. The drawstrings 16 are pulled to compress the device and thedevice is withdrawn into the delivery tube 14 for removal.Alternatively, the embolic protection device 10 may be stretchedlongitudinal with the aid of a catheter, which will cause the diameterof the device to contract. Alternatively, the embolic protection device10 may use a magnetic mechanism for compressing the device for removal.Multiple magnets 18 are arranged around the periphery of the device 10.After the procedure is completed, a catheter 20 carrying one or morestrong magnets 22 is inserted through the lumen of the device 10 tocompress the device around the catheter for removal.

FIG. 2 shows a stent-like embolic protection device 24 with waves orundulations 26 in the tubular mesh structure 28. The waves orundulations 26 in the embolic protection device 24 provide more surfacearea for filtering out potential emboli and prevents inadvertentocclusion of the arch vessels. This feature may be combined with any ofthe other embodiments and features of the invention described herein.

FIG. 3 shows a cut-away view of a stent-like embolic protection device30 wherein the tubular mesh structure 32 is constructed with two layersof mesh material. The embolic protection device 30 preferably has anouter layer 34 of fine mesh material and an inner layer 36 of coarsemesh material. The outer layer 34 is shown cut away so that the innerlayer 36 is visible. One or both layers of the device 30 may beself-expanding. For example, the outer layer 34 may be made of a finemesh textile fabric, while the inner layer 36 is made with aself-expanding wire mesh structure. The two-layer structure providesadditional protection against embolization and prevents the fine mesh ofthe outer layer 34 from becoming clogged with large emboli. Also,because blood can flow between the inner and outer layers of the device,all of the arch vessels will continue to receive blood flow even if theinner layer in front of one or more of the vessels becomes clogged. Thisfeature may be combined with any of the other embodiments and featuresof the invention described herein. For example, one or both layers ofthe two-layer construction may be made with waves or undulations asdescribed above in connection with FIG. 2.

FIG. 4 shows an alternative embodiment of an embolic protection device40. In this embodiment, the embolic protection device 40 may be madewith a panel of fine mesh textile fabric 42 that is supported on a wireframe 44 or the like. The panel of fine mesh fabric 42 is held in placeover the aortic arch vessels by the wire frame 44 to filter outpotential emboli. Being made of fabric, the mesh panel 42 is free toconform to the ostia of the arch vessels to allow more surface area forblood flow compared to a totally flat panel.

The wire frame 44 may be attached to a handle or cannula 46 forinsertion through an aortotomy or to a catheter 48 for peripheral arteryinsertion. Alternatively or in addition, the wire frame 44 may includeone or more wire hoops 50 or a stent-like tubular structure forsupporting the embolic protection device 40 within the aortic arch. Thisembodiment and/or its features may be combined with any of the otherembodiments and features of the invention described herein. For example,the mesh panel 42 may be made with waves or undulations as describedabove in connection with FIG. 2 and/or with a two-layer construction asdescribed in connection with FIG. 3. As a further example, the handle,cannula 46 or catheter 48 for insertion of the embolic protection device40 described in connection with FIG. 4 may also be combined with any ofthe embolic protection devices described in connection with FIGS. 1-3and 5.

FIG. 5 shows another alternative embodiment of an embolic protectiondevice 52. An inflatable toroidal balloon 54 supports the upstream endof a tubular mesh structure 56. The toroidal balloon 54 is inflated anddeflated through a catheter 58 having an inflation lumen and,optionally, a guidewire lumen. The tubular mesh structure 56 may be aself-expanding structure woven of wires or fibers or it may be aflexible textile mesh. Optionally, one or more wire hoops 60 or the likemay be used to support the tubular mesh structure 56 within the patent'saorta. Alternatively, one or more additional inflatable toroidalballoons 54 may be used in place of the optional wire hoops 60 tosupport the tubular mesh structure 56. The features of this embodimentmay be combined with any of the other embodiments and features of theinvention described herein. For example, one or more inflatable toroidalballoons 54 may be combined with the embolic protection devicesdescribed in connection with FIGS. 1-3 for supporting a tubular meshstructure or panel of mesh material.

The entire embolic protection device or a portion of it may be coatedwith an antithrombogenic coating, for example a bonded heparin coating,to reduce the formation of clots that could become potential emboli.Alternatively or in addition, the embolic protection device or a portionof it may have a drug-eluting coating containing an anti-inflammatory orantistenosis agent.

The embolic protection device of the present invention can also be usedfor embolic protection of other organ systems. For example, an embolicprotection device can be deployed in the patient's descending aorta forpreventing embolic particles in the aortic blood flow from entering therenal arteries and embolizing in the patient's kidneys.

While the present invention has been described herein with respect tothe exemplary embodiments and the best mode for practicing theinvention, it will be apparent to one of ordinary skill in the art thatmany modifications, improvements and subcombinations of the variousembodiments, adaptations and variations can be made to the inventionwithout departing from the spirit and scope thereof.

1. An embolic protection device for deployment within a patient's aortacomprising: a substantially flat panel of filter mesh material supportedon a wire frame, the wire frame surrounding a periphery of thesubstantially flat panel of filter mesh material, and at least onestructure connected to the wire frame configured for engaging aninterior wall of the aorta to support the embolic protection devicewithin the patient's aorta, the embolic protection device having acompressed position wherein the embolic protection device is compressedto a small diameter for insertion into the patient's aorta and anexpanded position wherein the embolic protection device expands to alarger size within the patient's aorta, wherein when the embolicprotection device is in the expanded position the at least one structureexpands away from a plane of the flat panel of filter mesh material to adeployed position configured to support the wire frame and the panel offilter mesh material within the aorta such that the wire frame conformsto an inner wall of the patient's aorta and the filter mesh allows bloodto enter the sidebranch vessels but prevents embolic material fromentering the sidebranch vessels.
 2. The embolic protection device ofclaim 1, wherein the support comprises at least one wire hoop connectedto the wire frame, extending away from the plane of the flat panel offilter mesh material and supporting the embolic protection device withinthe patient's aorta when the embolic protection device is in theexpanded position.
 3. The embolic protection device of claim 1, whereinthe wire frame supporting the panel of filter mesh material is aself-expanding structure.
 4. The embolic protection device of claim 1,wherein the filter mesh material is configured with waves orundulations.
 5. The embolic protection device of claim 1, wherein thepanel of filter mesh material is configured with a first layerconstructed of a fine mesh textile fabric and a second layer constructedof a self-expanding wire mesh structure.
 6. The embolic protectiondevice of claim 1, wherein the panel of filter mesh material isconfigured with a first layer of a coarse mesh material and a secondlayer of a fine mesh material.
 7. The embolic protection device of claim1, further comprising a delivery tube sized and configured to hold theembolic protection device in its compressed position.
 8. The embolicprotection device of claim 1, further comprising a drawstring encirclingthe tubular structure for selectively compressing the tubular structureto a small diameter for withdrawal from the patient.
 9. A method ofproviding embolic protection for sidebranch vessels connected to apatient's aorta comprising: introducing an embolic protection deviceinto the patient's aorta, the embolic protection device comprising awire frame supporting a substantially flat panel of filter meshmaterial, the wire frame surrounding a periphery of the substantiallyflat panel of filter mesh material, and at least one structure connectedto the wire frame an interior wall of the aorta to support the embolicprotection device within the patient's aorta, the embolic protectiondevice having a compressed position, wherein the embolic protectiondevice is compressed to a small diameter for insertion into thepatient's aorta; and expanding the embolic protection device to anexpanded position within the patient's aorta, wherein, when the embolicprotection device is in the expanded position, the at least onestructure expands away from a plane of the flat panel of filter meshmaterial to a deployed position configured to support the wire frame andthe panel of filter mesh material within the aorta such that the wireconforms to an inner wall of the patient's aorta and the filter meshmaterial and prevents embolic material from entering the sidebranchvessels but allows blood to enter the sidebranch vessels, wherein aportion of the at least one structure extending away from the flat panelof filter mesh material is not covered by or directly attached to thefilter mesh material.
 10. The method of claim 9, wherein the filter meshmaterial is configured with waves or undulations.
 11. The method ofclaim 9, wherein the panel of filter mesh material is configured with afirst layer constructed of a fine mesh textile fabric and a second layerconstructed of a self-expanding wire mesh structure.
 12. The method ofclaim 9, wherein the panel of filter mesh material is configured with afirst layer of a coarse mesh material and a second layer of a fine meshmaterial.
 13. The method of claim 9, further comprising compressing theembolic protection device into a delivery tube for introduction of theembolic protection device into the aorta.
 14. The method of claim 9,wherein the method further comprises drawing a drawstring encircling thetubular structure to compress the tubular structure to a small diameterprior to withdrawal from the patient.